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1. 发明专利

CA2219399A1 BULK FORMATION OF MONOLITHIC POLYSACCHARIDE-BASED HYDROGELS 未知
公开(公告)号：CA2219399A1
公开(公告)日：1999-04-24
申请号：CA2219399
申请日：1997-10-24
申请人： BIO SYNTECH LTD
发明人： COMBES CRYSTELLE , SELMANI AMINE , CHENITE ABDELLATIF , CHAPUT CYRIL
IPC分类号： C08B37/00 , C08B37/08 , C08L5/00 , C08L5/04 , C08L5/06 , C08L5/08
摘要： The present invention relates to compositions and methods for building monolithic massive hydrogels made of ionic polysaccharides such as Chitin, Chitosan, Alginate, Pectin, Hyaluronic Acid by specific in situ uniform pH changes. Low- to high-molecular weight polybase polysaccharide are dissolved at room temperature in acidic aqueous solutions (2% w/v, pH 4-6). An amide such the urea or ureid is added to the acidic polysaccharide solution and the mixture is homogenized and heated to 80-90.degree.C for initiating the hydrolysis of the amide and the in situ delivery of basic products. The resulting products basify uniformly and continuously the mixture allowing a pH-controlled gelation of the polybase (pH increase from 3-6 to 7-8). Optical signs of the polybase Chitosan gelation at 37.degree.C appear at pH 6.2-6.5. In a similar way, polyacid polysaccharides such as Alginate or Hyaluronan can be gelled from alkaline solutions by hydrolyzing ester or acid anhydride products such the maleic or acetic anhydride, or the beta-esters and liberating acids in situ. In both cases, the resulting materials are hydrogen-bond based monolithic massive hydrogels with good physico-mechanical properties, are easily moulded into complex shaped materials and present limited shrinkages. Polybase or polyacid-based monolithic hydrogels can be obtained with incorporated organic or inorganic components (second polymer or additive). Ionic polysaccharide may be applied to drug and cell delivery systems, implantable devices or encapsulating materials.

2. 发明专利

CA2212300A1 IN VITRO OR IN VIVO GELFYING CHITOSAN AND THERAPEUTIC USES THEREOF 未知
公开(公告)号：CA2212300A1
公开(公告)日：1999-02-04
申请号：CA2212300
申请日：1997-08-04
申请人： BIO SYNTECH LTD
发明人： COMBES CRYSTELLE , CHENITE ABDELLATIF
IPC分类号： A61K9/00 , A61K47/36 , A61L24/08 , A61L26/00 , A61L27/00 , A61L27/20 , A61L27/26 , A61L27/50 , A61L27/52 , C08L5/08 , A61K9/66 , A61K9/70
摘要： The present invention relates to composition, method and applications of loaded or unloaded Chitosan-.beta.-Glycerophosphate hydrogels are proposed for cosmetic, medical and surgical applications. Solid .beta.-Glycerophosphate is added and dissolved at low positive temperature (10.degree.C) within 0.5 to 3.0% w/v Chitosan in aqueous acidic solutions. The aqueous Chitosan-.beta.-Glycerophosphate solutions, initially stored at low positive temperatures, preferentially at 4.degree.C, are endothermally gelated within the temperature range of 30 to 60.degree.C, preferentially at 37.degree.C. The said Chitosan-.beta.-Glycerophosphate solution spontaneously transforms into a gel at the desired gelation temperature. Gelation can be ex vivo within any receivers or molds, or in situ in animals or humans so as to fill a tissue defect or cavity. Encapsulation of living cells or cellular matters is carried out by incorporating the said cells or cellular matters within the aqueous Chitosan-.beta.-Glycerophosphate solution at a low positive temperature (ideally at 4.degree.C), then by gelating the cells loaded Chitosan-.beta.-Glycerophosphate solution at the selected gelation temperature (ideally at 37.degree.C). Chitosan-.beta.-Glycerophosphate hydrogels without encapsulated living cells are selected for surgical reconstructive and regeneration uses and drug delivery purposes. Chitosan-.beta.-Glycerophosphate with encapsulated living cells are applied to the culture and engineering of artificial tissues as well as to the reconstruction of tissues. Engineering and regeneration of articular cartilage and cartilageous tissues are targeted through the injection and in situ gelation or the implantation of chondrogenic cells loaded in Chitosan-.beta.-Glycerophosphate systems.

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